Auto Hold
The auto hold feature can be activated and deactivated through the use of the auto hold switch. The feature defaults to activated when the ignition is set to ON and the following conditions have been met; the vehicle has come to a complete stop, the driver safety belt is buckled and the driver door is closed. The ABS module receives the driver safety belt buckle status from the RCM, driver door status from the BCM, brake system pressure and the wheel speed sensors allow the ABS module to determine if the vehicle is stopped.
Once the vehicle has come to a complete stop, the driver safety belt is buckled, the driver door is closed, and the driver has not deactivated the feature through the switch, the ABS module closes the isolation valves in the HCU to maintain the current brake system pressure at the wheel ends. The ABS module maintains the pressure until the driver presses the accelerator pedal, shifts the transmission into PARK or after a specific time limit has been reached. The ABS module engages the parking brake 2-10 minutes after the vehicle has stopped, depending on the grade of incline the vehicle is currently stopped on. The steeper the grade the shorter the time before the parking brake is engaged.